Not enough people are willing to purchase ethanol to justify a US government mandate, making it a costly way to reduce government emissions.

Ethanol, a corn derived fuel, is more expensive to make than gasoline. The fuel is sold at a loss or with subsidies.

A study of ethanol sales found a smaller than expected drop in ethanol consumption when the price per gallon went up by 10 cents. While more consumers than previously thought are willing to pay extra for ethanol, it’s not enough to justify a government mandate.

Under current United States federal law, renewable energy must be mixed into the nation’s fuel supply.